1. Field of the Invention
The present invention relates generally to an intake system for an internal combustion engine provided with a supercharger, and more specifically to an intake system which is arranged to lead the air from the supercharger directly to the engine through an air passage bypassing an air cooler under certain engine operating conditions, especially, at low engine load, thereby to prevent the intake air from being cooled excessively, while being capable of sufficiently cooling the intake air at higher engine loads.
2. Description of the Prior Art
A supercharger for an internal combustion engine increases the amount of intake air for the engine by pressurizing the air. The compression of air by a supercharger, however, raises the temperature of the air and increased temperature intake air increases the heat load exerted upon the engine and is liable to cause abnormal combustion such as knock or detonation. Accordingly, it is usual to provide an air cooler between the supercharger and engine to cool the air from the supercharger. However, cool air is rather undesirable under some engine operating conditions. That is, at low speed and low load, low temperature intake air makes combustion incomplete and impairs the engine operation stability and fuel consumption.